Submitted by Lambda, also found by Trust and IllIllI
https://github.com/code-423n4/2022-12-tessera/blob/1e408ebc1c4fdcc72678ea7f21a94d38855ccc0b/src/modules/GroupBuy.sol#L265
https://github.com/code-423n4/2022-12-tessera/blob/1e408ebc1c4fdcc72678ea7f21a94d38855ccc0b/src/modules/GroupBuy.sol#L283
Both usages of call do not check if the transfer of ETH was succesful:
This can become very problematic when the recipient is a smart contract that reverts (for instance, temporarily) in its receive function. Then, GroupBuy still assumes that this ETH was transferred out and sets the balance to 0 or deletes userContributions[_poolId][msg.sender], although no ETH was transferred. This leads to a loss of funds for the recipient.
We assume that the recipient is a smart contract that performs some logic in its receive function. For instance, it can be a nice feature for some people to automatically convert all incoming ETH into another token using an AMM. However, it can happen that the used AMM has too little liquidity at the moment or the slippage of a swap would be too high, leading to a revert in the receing contract. In such a scenario, the GroupBuy contract still thinks that the call was succesful, leading to lost funds for the recipient.
require that the call was successful.
HickupHH3 (judge) commented:
stevennevins (Tessera) confirmed and mitigated:
